I’m known for being a bit of a purist with my retro PC builds. Sure I’ll make exceptions at times, use a CF or SDD HDD here and there (out of sight out of mind right?), use a CD-ROM or DVD drive in a system that probably wouldn’t of had one back in the day or even throw a floppy emulator into some problematic floppy only systems but generally I like to stick to period correct builds with hardware more or less from the time period. With this build though I’m going to step away from that a little bit and build what I call DOSzilla, A super powerful yet highly compatible DOS based gaming PC with key parts more or less outside of the era that DOS was a prevalent or even moderately used as a operating system in the home.

One of the pickiest components when building a DOS PC is the sound card. DOS always works best with a 16-bit ISA sound card. There are PCI sound cards like those based on the Aureal Vortex chip that do a pretty good job of working under DOS, especially with later games but I wanted to go for as high of a compatibility and ease of use as I could and this meant I needed a motherboard with a 16-bit ISA slot. This basically limits us to either a Pentium III motherboard that supports up to a 1.4ghz Tualatin CPU or a AMD Athlon socket A Thunderbird motherboard that supports up to a 1.4ghz AMD Thunderbird CPU. There are motherboards that support faster CPU’s as well as having a 16-bit ISA slot but they tend to be for industrial applications and are expensive and hard to find so for this project I wanted to keep costs low and components easily attainable.

If your wondering about performance between the Intel 1.4ghz Tualatin and the AMD 1.4ghz Thunderbird they are relatively similar but it depends on the application and game. Here is an example of some benchmarks I performed using this motherboard and a separate PIII board though note different motherboards may give varying results.

Motherboard – Tyan S2390

Either motherboard choice is fine but I went with a AMD board just for something a little different. The motherboard I chose was the Tyan S2390, a socket A board which uses the VIA KT-133 chipset.

This is a pretty good performing motherboard that met my immediate needs. It supported a Thunderbird 1.4ghz CPU (though that manual states it can only accept up to a 1ghz CPU) had a x4 AGP slot, BIOS options to disable internal cache and finally had one all important 16-bit ISA slot.

For my operating system I’m just using my old fallback of DOS 6.22 but if your feeling adventurous you could try DOS 7.1 which some people have managed to isolate from Windows 9x and make into its own standalone OS. This MAY induce a few compatibility issues with a rare few picky games but on the upside you can use much larger hard drive sizes and partitions.

CPU – AMD 1.4ghz Thunderbird

So first we need to talk about my choice of CPU, the AMD 1.4ghz Thunderbird.

Image courtesy of Wikipedia

Released in 2001 the 1.4ghz model is the final and fastest CPU in AMD’s Thunderbird core chips. Things to note is this CPU can be a little hard to find as well as it runs a little hot so make sure you use a decent heatsink / fan combo. This CPU is also the fastest CPU my motherboard will accept even though official documentation says it will only support CPU’s of up to 1ghz this is probably because the motherboard came out roughly a year before the 1.4ghz Thunderbird was a thing.

I also like this motherboard / CPU combo because although 2001 is well after the death of DOS as a mainstream home OS or platform for gaming it’s not to far out of the era to count as ridiculous overkill as bigger DOS titles were still being released in 97 and probably 98 only three or so years earlier. All the extra horsepower does have one big advantage and that’s running many of these later DOS titles much smoother then PC’s of their time could especially in higher resolutions that games such as Quake offered.

One major downside of such speed though is greater incompatibility with games due to mostly speed issues. This results in some titles running far to quickly or sometimes more subtle issues such as a game appearing to run fine but timed events hidden in the background running to quickly. This can be especially prevalent with older titles where a CPU was expected to be running at a mere 33mhz or 66mhz let alone 1.4ghz.

This issue can be mitigated somewhat by the BIOS option to disable internal cache on the CPU. My testing with programs like Topbench has shown when the internal cache is disabled in BIOS on the 1.4ghz Thunderbird it performs similar to a 33-50mhz 486DX.

RAM – PC133 SDRAM

For RAM I’m using one stick of 512MB PC133 SDRAM. This is actually massive overkill and may actually adversely effect compatibility with a few rare titles. I’m just using it for the sake of trying it but if you want to play things safer a 128mb stick or even a 64mb stick would be best. If though your planning on duel booting Win 9x or running Windows as your main OS and using DOS mode stick with 512mb.

HDD – Maxtor ATA133 HDD & Promise ATA100 PCI IDE controller

The Tyan S2390 only has ATA66 on the built in IDE controller which although adequate I wanted to go a bit faster. For a hard drive I could easily have thrown in a SATA adapter and a SSD or even SD card as a hard drive but I wanted to just go with something I already had laying around so I opted for a 40GB Maxtor ATA133 hard drive with a PCI ATA100 IDE card I had on hand. using this card I do lose a bit of performance from the I could of gotten out of the hard drive as well as wasting a lot of hard drive space as my setup can only see 2GB of the hard drive.

If you have one lying around or want to spend the few extra dollars you shouldn’t have any issues with throwing in a PCI SATA adapter card and a SATA hard drive or even SSD.

Video – Diamond Stealth S540 Savage 4 Pro

For a video card I wanted to go with something very capable and fast but also a card that gave the highest compatibility with older DOS titles. For this I went with the AGP S3 Savage 4 pro chip in the form of the 32mb Diamond Stealth III S540

S3 cards from the mid 90’s such as the S3 Trio and Virge were known for their excellent and highly compatible 2D core and the Savage 4 chip is no different. Also like their earlier cards the Savage 4 wasn’t really known as being a speed demon and was generally outclassed by cards from Nvidia and 3DFX such as the TNT2 and Voodoo 3 but in our DOS build the Savage 4 based S540 is more then powerful enough as well as delivering that excellent 2D image and compatibility. The card I’m using here is the AGP x4 pro chip but if you want a card a little faster look for the Savage 4 Xtreme.

Sound – Creative AWE64

Lastly we have the sound card. Obviously we I wanted to go with a 16-bit ISA card for a large degree of hassle free DOS compatibility. The card I ended up going with largely for for the reason of having one in easy reach was the Creative AWE64.

Keep in mind there are many acceptable sound cards one can use for this project. I went with the AWE64 for its good compatibility and sound quality. In DOS the AWE64 acts just like an AWE32 and many later DOS games directly support it in setup options, otherwise it usually can emulate a SB pretty well. It also can do its own MIDI which although usually not as good as an external module still sounds acceptable with many later games. It does have its drawbacks though such as a lack of a real OPL FM chip but since this PC is heavily geared to later games that would take more advantage of MIDI or a CD soundtrack I felt it was a still a great choice. This model also lacks a wavetable header so no MIDI daughterboard add-ons. Again though, if you have a different preference many other ISA cards should work just fine such as an AWQE32 with a MIDI daughterboard of your choosing or a Sound Blaster 16 or clone.

Games, Overall Performance and Conclusion

Now to take a look at how this PC performed for me once all put together. First a look at some Benchmarks with my more period correct Pentium based fast DOS PC

As expected DOSzilla stomps the Pentium 1 PC. For some reason my benchmark for Wolf3d wouldn’t even run on the Pentium rig but this could be due to anything. Some benchmarks turn out surprisingly close though like DOOM. If my terrible math skills are correct it’s only about 30% slower on the Pentium MMX PC.

As for games I did test a number of them including a few older titles. The games I tested and the results are

DOOM – no issues

Quake – no issues

Tex Murphy, Under a Killing Moon – no issues

Duke Nukem 3D – no issues

Decent 2 – ran to fast, corrected by disabling CPU cache in BIOS

Commander Keen 4 – no issues

Star Wars Dark Forces – no issues

Wolfenstein 3D – no issues

Double Dragon – no issues

Major Stryker – failed to install (this is due to a installer bug if your hard drive is to big, even happens on a 386 if the HDD is > 1GB)

Even though I didn’t play any of these games on DOSzilla extensively I was surprised by the initial excellent compatibility. most of the late era games ran just fine with pretty much zero issues in gameplay, graphics or setting up the sound in the install. Everything just worked for the most part. Decent 2 did run to fast but restarting and turning off internal CPU cache in the BIOS options corrected this. Major Stryker failed to install but this was due to the HDD being to large which happens on any PC regardless of the CPU if you use a HDD > 1GB. Of course this is a very small sampling of DOS games from a library of thousands so there is bound to be compatibility issues especially in older titles but overall I was impressed by the initial trials.

As for Quake and some of its ridiculously taxing resolution options for the time DOSzilla was able to run the game in 1280 x 1024 though gameplay was not optimal and quite choppy. It was technically playable but not a great experience. I suspect a fast video card could help in this department. The game did run at a perfectly acceptable framerate at 1024 x 768 though.

In conclusion I think DOSzilla makes a fine DOS PC. I still prefer a more traditional retro PC using a bit more period correct parts. I feel a slower machine does offer better all around compatibility and just feels a bit more special. That said I was impressed with DOSzillas compatibility, at least with later DOS titles likely due to the 16-bit ISA sound card and S3 video. The ability to actually play games like Quake in higher resolutions was nice but as I said I suspect more and more issues with CPU speed would crop up as you played more and more older titles. All in all if you have the parts and are looking for a DOS rig with an emphasis on playing late 90’s games go ahead and build your own DOSzilla.

Like this:

Related

9 Comments

Quite an interesting build. Makes me feel old though, seems like not all that long ago I had a Socket A machine as my main rig.

For the games that had closer benchmark scores it’s possible that the FPS was deliberately limited by VSync. Doom in particular. The developers did this to remove screen tearing when the screen is updated. 3d Bench seems to be more indicative of how much difference there can be in CPU performance. Also it’s interesting how much performance difference the internal cache setting makes. I wouldn’t expect it to be that large.

I never had a socket A PC at the time. I had a 1ghz Pentium III machine forever before I finally upgraded to a socket 939 machine. Good point about the Vsync, Its pretty simple to disable in Windows using something like Powerstrip but I’m not sure if its doable in DOS. As for disabling the cache I’m also surprised how effective it is. works well with a super socket 7 k6-III as well, basically turns them into 386 CPU’s. speed wise.

Remember what I said about the Barton being faster than the Thunderbird? One of the main reasons it’s faster is due to changes in the CPU cache, so for games that you’re already disabling the cache on, you shouldn’t run into problems by migrating to Barton.

Speaking of V-Sync, actually… I once installed Unreal Gold on a brand new computer a few years ago, featuring an Intel 2500K, 8 Megabytes of RAM, an Nvidia GTX 650 TI and Windows 7 Enterprise 64-Bit.

The game ran well. Too well. It was at least a couple hundred frames per second, even on the maximum in-game settings, and the game was playing everything at hyperspeed. I fixed it by enabling Adaptive V-Sync in the Nvidia Control Panel.

Unreal is one of those games that, at first, seems like it will always run at the correct speed, as it is not directly tied to the speed of any particular piece of hardware. However, once it breaks the 100 frames per second barrier, it will start speeding up by insane margins.

What I suspect is that the speed of the game is actually tied directly to the framerate, but they manually programmed an adjustment for different framerates that they expected the game to run at in the future. Unfortunately, they didn’t quite anticipate computers would actually become fast enough to break the 100 FPS barrier before the next decade was over.

Heh, That always seems to be the case. So many programmers just never seem to anticipate the speed at which computers advance. you would think by the late 90’s more wouldn’t of underestimated the rate of advancement.

You could have used an AMD Barton CPU instead, if you wanted to get even more performance. It uses Socket A, just like the Thunderbird. You might need to significantly underclock it so that it will still run on your motherboard, but it would still be faster and more energy efficient than that you got.

In regards to installing Major Stryker, you could try first installing it on another DOS PC with a much tinier hard-drive, and then just copying all the files over onto the DOSZilla’s drive. And if you have the time, you could actually go ahead and migrate your entire system to a small SSD.

As for industrial motherboards which support 16-bit ISA cards, if you don’t mind digging through thrift stores full of outdated and abandoned electronics, you can probably find exactly what you’re looking for without leaving an intergalactic void in your wallet.

Finally, the various games that run too fast, it might be possible to write up the names and locations of the executables into a list that would be loaded by a kernel-mode program so that you could let the computer automatically adjust certain system settings for those games specifically. Alternatively, there are probably patches for those games online that will fix them for running on overpowered computers.

that’s a good idea about Major Stryker and the other games. Finding patches for correcting speeds in games can be hit or miss but I’m sure some games do have them.

Right now my friend is borrowing Doszilla to experiment with some games hes having issues with on his PC but when I get it back I’ll try a later socket A CPU. I just assumed a none Thunderbird CPU would not work. I know it’s the same socket but I assumed the CPU was different enough hat the motherboard wouldn’t support it. I’ll certainly try it though.

As for a P4 industrial MB, I actually found one for $15 locally at a thrift. Caps are all bad though so its going to be a minute before I can do a write up on it. thanks for the comments and suggestions.

By the way, if you have any leftover slots, you could probably plug in additional sound cards or video accelerators of different models in order to extend your compatibility to a wider range of games. Not sure if DOS would actually allow that, though.

I think I’ve seen that done with sound cards if you have enough resources to assign them to different IRQ’s ect… as for video you could install a PCI card of a different type and I think there is an option in the BIOS to assign the primary video adapter as AGP or PCI. adding a Voodoo 1 or 2 would also achieve this though I’m saving that for another article.